The P135SJ convert s a a door from an in/out-swing door to an out-swing only. Most of the self centering hinges have a built in 5° offset pivot pin. The offset pin makes the door center 5° to the inside of the shower. This feature make s the door apply slight pressure on to the P090SJ seal. It not only assures that the door stays shut, it also make the seal water tight. It also gives the door a real solid closing action. Adjustable hinges can be used in a similar way. Remove the seal and adjust the door so it stops 5° to the inside of the shower. Replace the seal and you all set.